The subject invention is directed to methods and apparatus for facing cylindrical workpieces such as tube and pipe ends or the like. More particularly, the invention is directed to facing tools for accommodating a variety of tube/pipe sizes while preventing unwanted vibration and movement of the workpiece and tool during a facing operation.
Metal tubes and pipes are commonly used as conduits for fluids such as gases and liquids used in a wide variety of applications. Often these conduits run throughout a facility over great distances. Tubes and pipes are manufactured in a variety of lengths and sizes. In order to assemble the conduits in long runs, a plurality of such conduits may be butt welded together end to end. The conduits further may be welded to various flow control devices such as valves, mass flow meters, manifolds, elbows and so on. The tube or pipe typically is cut to a specified length by any convenient means such as a tube cutter or even a hacksaw.
A cut tube or pipe end usually is not in good condition for immediate welding. The cut end of such a workpiece is finished or xe2x80x9cfacedxe2x80x9d so that the end is square and chips, burrs and other anomalies are removed. This provides a tube or pipe end that can then be more easily welded to another tube or pipe end, flow device or other tube/pipe end attachment.
The cut end is prepared using a facing tool. Generally, facing tools have a cutting tool that is rotated by a motor or other drive device. The cutting tool is brought into contact with the end of the workpiece and shaves off material from the cut end to form a clean square end.
Known facing tools have a number of design features that limit their overall usefulness. Such tools, for example, do not adequately hold the workpiece still during a facing operation. With the cutting tool rotating at high speed, vibration of the cutting tool itself or movement and vibration of the workpiece can reduce the overall quality of the finished end, possibly necessitating additional facing, manual re-work or scrap.
Known facing tools further suffer from limitations on the workpiece diameters that can be faced using a specific tool configuration. Tubes and pipes, for example, often are used in sizes ranging from xe2x85x9-inch to 2-inch diameters in quarter- or half- inch increments or less. On a typical shop floor, a facing tool may need to be used on a variety of such sizes. Known tools require substantial re-configuration when the facing tool is used to face different sized workpieces. In some cases, both the fixture that holds the workpiece as well as the cutting tool must be changed to accommodate the next workpiece size. This further necessitates additional parts for the facing tool which must be carried with the tool to the job site.
It is desired, therefore, to provide a facing tool that substantially reduces workpiece and cutting tool vibration while at the same time permitting a variety of workpiece sizes to be faced with less re-configuration of the facing tool.
In accordance with one embodiment of the invention, a facing tool includes a fixture that securely holds a workpiece, and a fixture retainer that secures the fixture against axial and radial movement during a facing operation. In one embodiment, the fixture includes a two piece construction that allows a first piece to be swung away from the second piece to accommodate a variety of sizes of workpieces.
In accordance with another aspect of the invention, a facing tool includes a tool spindle that has a cutting tool insert mounted thereon wherein the cutting tool insert is positively loaded against of surface of the spindle to reduce vibration and movement of the tool during a facing operation. In accordance with another aspect of the invention, the spindle is formed with number of recesses or pockets that can receive a cutting tool to allow for facing operations on different sized workpieces. Still a further aspect of the invention is the provision of a chip shield that deflects material removed by the cutting tool away from the workpiece during the facing operation.